Conjugation of mussel‐inspired catechol groups to various polymer backbones results in materials suitable as silicon anode binders. The unique wetness‐resistant adhesion provided by the catechol ...groups allows the silicon nanoparticle electrodes to maintain their structure throughout the repeated volume expansion and shrinkage during lithiation cycling, thus facilitating substantially improved specific capacities and cycle lives of lithium‐ion batteries.
High power conversion efficiency (PCE), long‐term stability, and mechanical robustness are prerequisites for the commercial applications of organic solar cells (OSCs). In this study, a new ...star‐shaped trimer acceptor (TYT‐S) is developed and high‐performance OSCs with a PCE of 19.0%, high photo‐stability (t80% lifetime = 2600 h under 1‐sun illumination), and mechanical robustness with a crack‐onset strain (COS) of 21.6% are achieved. The isotropic molecular structure of TYT‐S affords efficient multi‐directional charge transport and high electron mobility. Furthermore, its amorphous structure prevents the formation of brittle crystal‐to‐crystal interfaces, significantly enhancing the mechanical properties of the OSC. As a result, the TYT‐S‐based OSCs demonstrate a significantly higher PCE (19.0%) and stretchability (COS = 21.6%) than the linear‐shaped trimer acceptor (TYT‐L)‐based OSCs (PCE = 17.5% and COS = 6.4%) and the small‐molecule acceptor (MYT)‐based OSCs (PCE = 16.5% and COS = 1.3%). In addition, the increased molecular size of TYT‐S, relative to that of MYT and dimer (DYT), suppresses the diffusion kinetics of the acceptor molecules, substantially improving the photostability of the OSCs. Finally, to effectively demonstrate the potential of TYT‐S, intrinsically stretchable (IS)‐OSCs are constructed. The TYT‐S‐based IS‐OSCs exhibit high device stretchability (strain at PCE80% = 31%) and PCE of 14.4%.
A new star‐shaped trimer acceptor (TYT‐S) is developed. The organic solar cells (OSCs) using TYT‐S exhibit a high power conversion efficiency (PCE) of 19.0% and long‐term stability, as well as excellent mechanical robustness (crack‐onset strain = 21.6%). Consequently, intrinsically stretchable OSCs using TYT‐S achieve high PCE and device stretchability at the same time, highlighting great potential for wearable applications.
Human skin plays an important role in hand manipulation by making a stable grasp with an enlarging contact area while providing a firm hold on the object. However, satisfying these two functions is ...contradictory in conventional single‐layer artificial skin. Softer skin material would increase the contact area, which is advantageous in maintaining the stability, but it decreases the manipulability since the object tends to make uncontrollable movement within the softer skin, and vice versa for harder skin material. This paper presents a biomimetic three‐layer skin structure inspired by human palm skin and shows that both stability and manipulability can be enhanced with the three‐layer structure. To achieve the unique stiffness characteristics of the human palm skin, a porous latex structure, which is highly compressible but tough in tensile direction, is chosen as the subcutaneous fat layer. Through the novel experimental setup and the finite element method simulations, it is found that the porous latex structure is the key structure contributing to both stability and manipulability. Furthermore, it is demonstrated that a robotic hand with the proposed skin material shows enhanced robustness in grasping tasks. With the proposed skin material, the robotic hands would be more advantageous for challenging manipulation tasks.
Human skin plays an important role in hand manipulation by enabling a stable grasp with an enlarging contact area while providing a firm hold on the object. Here, a biomimetic skin material inspired by the human palm skin is developed and shows both enhanced stability and manipulability of hand manipulation. With the proposed skin, the robotic hands will be more advantageous for challenging manipulation tasks.
Interface modification of perovskite solar cells (PSCs) has been widely explored not only to achieve defect passivation but also to facilitate charge transport and stabilize the physical/electrical ...contact at device interfaces. In this study, 2‐(9H‐carbazol‐9‐yl)ethylphosphonic acid (CEPA) is introduced as an interface modifier at the interface of perovskite and the hole transporting material (HTM) layer into n‐i‐p PSCs. CEPA reduces surface traps, manipulates the surface dipole for energy‐level alignment, and induces molecular interaction at the interface of the CEPA‐HTM for enhanced interfacial adhesion energy and good mechanical stability. The power conversion efficiency of interface‐optimized PSC is 23.6% using a 2D/3D perovskite structure, representing the highest efficiency among poly(triarylamine) HTM‐based devices. The encapsulated CEPA‐treated PSCs maintain nearly 90% of their initial efficiency during a damp heat lasting for more than 1530 h and retain their initial efficiency during continuous operation under illumination.
An interface modifier (IM) that interacts not only with perovskite but also with hole transporting material is introduced for efficient and stable perovskite solar cells. The best solar cell employing rational IM exhibits a power conversion efficiency of 23.6% with a 2D/3D perovskite structure. Thermal and operational stabilities of interface‐optimized devices are demonstrated.
Recyclable conjugated polymers are important for realizing eco‐friendly electronics with advantages of solution processability and flexibility. A recyclable conjugated polymer, PY‐TIP is developed, ...of which a key monomer is successfully extracted via a mild depolymerization process and is reused for the synthesis of novel conjugated polymers. One‐shot preparation of polymer acceptor and its bulk‐heterojunction (BHJ) is demonstrated from the recycled monomer, Y5‐TA, for the first time and the resulting BHJ film shows optimal nanoscale morphology for efficient charge generation and transport. As a result, the solar cells prepared using the BHJ film show a higher efficiency of 13.08% and much improved thermal and mechanical stability compared with those based on the small molecular acceptor. These results are important in that the various polymers can be prepared from the recycled monomer in a solid state without organic solvents and purification step and this strategy is effective for improving the thermal and mechanical stability of the BHJ film as well as achieving high photovoltaic performance. PY‐TIP is exemplary in that it can reproduce its monomer which can be used to synthesize conjugated polymers with novel chemical structures and physical properties. This work provides a design guideline for developing recyclable conjugated polymers with dynamic covalent bonds.
Recyclable conjugated polymer is developed and gives the recycled monomer via a mild depolymerization process. The recycled monomer utilizes for the network acceptor polymer through one‐shot preparation and the solar cells utilizing the BHJ achieved higher power conversion efficiency of 13.08% with higher thermal and mechanical stability than small molecular acceptor‐based BHJs.
Lead sulfide (PbS) colloidal quantum dots (CQDs) are promising materials for next-generation flexible solar cells because of near-infrared absorption, facile bandgap tunability, and superior air ...stability. However, CQD devices still lack enough flexibility to be applied to wearable devices owing to the poor mechanical properties of CQD films. In this study, a facile approach is proposed to improve the mechanical stability of CQDs solar cells without compromising the high power conversion efficiency (PCE) of the devices. (3-aminopropyl)triethoxysilane (APTS) is introduced on CQD films to strengthen the dot-to-dot bonding via QD-siloxane anchoring, and as a result, crack pattern analysis reveals that the treated devices become robust to mechanical stress. The device maintains 88% of the initial PCE under 12 000 cycles at a bending radius of 8.3 mm. In addition, APTS forms a dipole layer on CQD films, which improves the open circuit voltage (V
) of the device, achieving a PCE of 11.04%, one of the highest PCEs in flexible PbS CQD solar cells.
Continuous detection of raised intraocular pressure (IOP) could benefit the monitoring of patients with glaucoma. Current contact lenses with embedded sensors for measuring IOP are rigid, bulky, ...partially block vision or are insufficiently sensitive. Here, we report the design and testing in volunteers of a soft and transparent contact lens for the quantitative monitoring of IOP in real time using a smartphone. The contact lens incorporates a strain sensor, a wireless antenna, capacitors, resistors, stretchable metal interconnects and an integrated circuit for wireless communication. In rabbits, the lens provided measurements that match those of a commercial tonometer. In ten human participants, the lens proved to be safe, and reliably provided accurate quantitative measurements of IOP without inducing inflammation.
Flexible and wearable pressure sensors have attracted a tremendous amount of attention due to their wider applications in human interfaces and healthcare monitoring. However, achieving accurate ...pressure detection and stability against external stimuli (in particular, bending deformation) over a wide range of pressures from tactile to body weight levels is a great challenge. Here, we introduce an ultrawide-range, bending-insensitive, and flexible pressure sensor based on a carbon nanotube (CNT) network-coated thin porous elastomer sponge for use in human interface devices. The integration of the CNT networks into three-dimensional microporous elastomers provides high deformability and a large change in contact between the conductive CNT networks due to the presence of micropores, thereby improving the sensitivity compared with that obtained using CNT-embedded solid elastomers. As electrical pathways are continuously generated up to high compressive strain (∼80%), the pressure sensor shows an ultrawide pressure sensing range (10 Pa to 1.2 MPa) while maintaining favorable sensitivity (0.01-0.02 kPa
) and linearity ( R
∼ 0.98). Also, the pressure sensor exhibits excellent electromechanical stability and insensitivity to bending-induced deformations. Finally, we demonstrate that the pressure sensor can be applied in a flexible piano pad as an entertainment human interface device and a flexible foot insole as a wearable healthcare and gait monitoring device.
Abstract
All‐polymer solar cells (all‐PSCs), using polymerized non‐fullerene acceptors (PNFAs), have shown promise in improving device stabilities compared to small‐molecular acceptor‐based PSCs. ...However, low mixing entropy between polymer donors (
P
D
s) and PNFAs hampers the development of optimized blend morphology. Herein, this study develops efficient conjugated polymers that serve as interfacial compatibilizers between host
P
D
and PNFA. Ternary all‐polymer blends containing the compatibilizer demonstrate improved blend morphology with strengthened interfaces, resulting in better photovoltaic properties and thermal/mechanical stabilities. In detail, the power conversion efficiency (PCE) increases from 15.4 to 17.1% upon the addition of the compatibilizer. Moreover, the devices based on the ternary blend enable good thermal stability, retaining 90% of the initial PCE after 96 h at 125 °C. Additionally, the mechanical properties are improved; the cohesive fracture energy (
G
c
) of 2.6 J m
−2
and crack onset strain (COS) of 20.4% of the ternary blend outperform those of the binary blend (
G
c
= 1.1 J m
−2
and COS = 16.5%). Resultingly, the stretchable PSCs based on the ternary blend exhibit an excellent PCE of 13.7% and stretchability with a strain at PCE
80%
of 35%.
Herein, a high‐performance copper nanowire (Cu NW) network (sheet resistance ≈ 17 Ω sq−1, transmittance 88%) fabricated by plasmonic‐tuned flash welding (PFW) with ultrafast interlocking and ...photochemical reducing is reported, which greatly enhance the mechanical and chemical stability of Cu NWs. Xenon flash spectrum is tuned in an optimized distribution (maximized light intensity at 600 nm wavelength) through modulation of electron kinetic energy in the lamp by generating drift potential for preferential photothermal interactions. High‐intensity visible light is emitted by the plasmonic‐tuned flash, which strongly improves Cu nanowelding without oxidation. Near‐infrared spectrum of the flash induced an interlocking structure of NW/polyethylene terephthalate interface by exciting Cu NW surface plasmon polaritons (SPPs), increasing adhesion of the Cu nanonetwork by 208%. In addition, ultrafast photochemical reduction of Cu NWs is accomplished in air by flash‐induced electron excitations and relevant chemical reactions. The PFW effects of localized surface plasmons and SPPs on junction welding and adhesion strengthening of Cu network are theoretically studied as physical behaviors by finite‐difference time‐domain simulations. Finally, a transparent resistive memory and a touch screen panel are demonstrated by using the flash‐induced Cu NWs, showing versatile and practical uses of PFW‐treated Cu NW electrodes for transparent flexible electronics.
Plasmonic‐tuned flash copper (Cu) nanowelding is developed for high‐performance Cu nanowires (NWs) with interlocking on plastics. In addition, rapid photochemical reduction of oxidized Cu NWs is demonstrated in air. Finally, a transparent resistive memory and a touch screen panel are fabricated by using the Cu NWs.
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